BioCycle September 2007, Vol. 48, No. 9, p. 57
Generation of electricity from LFG makes up about two-thirds of current methane recovery projects in the United States.
Brian Guzzone and Chad Leatherwood
MOST PEOPLE think of landfills as a necessary evil at best, but our current primary method of waste management generates a by-product with significant energy value – landfill gas (LFG). Collection and control of LFG results in significant reductions in greenhouse gas (GHG) emissions. With the greater focus on climate change, a burgeoning market for GHG emission offsets is emerging and landfills can bring these GHG offsets to market, resulting in additional incentives for collection and beneficial use. With greater focus on development of domestically-generated alternate fuel sources, use of LFG to provide an energy source for biofuel production is an attractive option that has already been implemented. This article will review benefits of LFG-to-energy projects and how LFG has been successfully used.
Landfill gas is the natural by-product of the decomposition of organic waste in landfills and is comprised primarily of methane, the main component of natural gas, and carbon dioxide. Instead of allowing LFG to escape into the air, it can be captured, converted and used as an energy source. Using LFG has multiple benefits, such as reducing odors and other hazards associated with LFG emissions and preventing methane from migrating into the atmosphere where it contributes to local smog and global climate change. Methane is a potent greenhouse gas, about 21 times more so than carbon dioxide.
Landfill gas is extracted from landfills using a series of wells and a blower/flare (or vacuum) system. This system directs the collected gas to a central point where it can be processed and treated depending upon ultimate use. From this point, the gas can be flared, or used to generate electricity, replace fossil fuels in industrial and manufacturing operations fuel greenhouse operations, or be upgraded to pipeline quality gas.
EPA’s Landfill Methane Outreach Program (LMOP) has seen a dramatic increase in projects over the past ten years. Currently 424 projects are on line in the United States alone, and over 1,100 worldwide. According to EPA, at least 560 landfills exist that could economically support a project. These landfills would have a generation capacity of over 1,300 MW or could supply 250 billion cubic feet per year of gas to industrial end users.
Generation of electricity from LFG makes up about two-thirds of the current operational projects in the United States. Electricity for on-site use or sale to the grid can be generated using a variety of different technologies, including internal combustion engines and turbines. Some electrical generation projects increase overall efficiency by using waste heat from the generating device to provide hot water or steam for another use.
Direct use of LFG to offset another fossil fuel is occurring in about one-third of the current operational projects. This direct use of LFG can be in a boiler, dryer, kiln, greenhouse or other thermal applications. LMOP is also observing a growing trend in LFG-powered alternative energy projects where LFG provides low-cost fuel for use in such activities as biodiesel and ethanol production. Planned projects are also in development for conversion of LFG to methanol for use as a feedstock for biodiesel production.
MARKET DRIVERS FOR LFG UTILIZATION
Use of LFG as an energy source for projects such as biofuel production is driven by both economic and environmental considerations. Energy costs have increased significantly over the past decade, show greater volatility and are subject to extraneous activities, such as hurricanes, that are outside the control of fuel consumers. Higher prices not only encourage energy users to look for less expensive sources, but they make project economics more attractive. Industries of all types seek to become more competitive by reducing fuel costs, and communities have been able to attract new businesses by marketing LFG as a low-cost energy resource. Additionally, LFG projects have been instrumental in creating jobs, expanding local economic output and increasing tax revenue in economically stagnant areas.
Biofuel manufacturers are realizing significant savings on their energy costs when they use LFG in addition to providing a mechanism for meeting environmental goals. At the Abengoa Bioenergy Corporation ethanol production plant in Wichita, Kansas, use of LFG has provided an estimated cost savings of $1.4 million per year due to the reduced use of natural gas.
For the past two years in a row, LFG-powered biodiesel production facilities have received Project of the Year awards from LMOP. In 2006, Denton, Texas was recognized for development of a three million gallon per year biodiesel facility that uses waste oils to produce fuel for the city’s diesel fleet. Jackson County, North Carolina won the 2007 Project of the Year award for their LFG-fired biodiesel production facility that was developed in conjunction with an art and agriculture complex.
Economic benefits are certainly a powerful motivator but environmental stewardship and corporate social responsibility also are strong market drivers for landfill gas projects. Demand for GHG reductions has resulted in another motivation for the use of LFG – generation of GHG emission offsets through collection and control of LFG. According to the Chicago Climate Exchange, GHG offsets currently are trading for over $3/metric ton of CO2 equivalent (CO2E). Given that the capture of one ton of methane is equivalent to reducing approximately 20 tons of CO2E, LFG projects can provide significant GHG reductions for additional financial incentive.
IS A LANDFILL GAS TO ENERGY PROJECT IN YOUR FUTURE?
LMOP has a number of tools that can help determine if a landfill gas energy project is in your future. LMOP offers technical support that includes finding a landfill, estimating gas and energy generation potential, evaluating project possibilities, identifying applicable project incentives and conducting project economic analysis (see www.epa.gov/lmop for more information).
Landfill gas energy projects involve citizens, nonprofit organizations, local governments and industry in sustainable community planning and creative partnerships. These projects go hand-in-hand with community and corporate commitments to cleaner air, renewable energy, economic development, improved public welfare and safety and GHG reductions. By assisting in the development of innovative ways to use LFG, LMOP is able to simultaneously promote environmental protection and economically beneficial projects.
Brian Guzzone is Program Manager with the EPA Landfill Methane Outreach Program in Washington, DC. (firstname.lastname@example.org) Chad Leatherwood is with SCS Engineers in Asheville, NC (email@example.com).